JPH0632082A - Dampening water composition for lithography - Google Patents

Abstract

PURPOSE:To inhibit filling up of ink in a water rod of a printing press and peeling of an ink supply roller and to extend a water tolerance by incorporating water-soluble sugars in a dampening water for lithography. CONSTITUTION:Water-soluble sugars (e.g. glucose) are incorporated in dampening water by 0.10-1.0wt.%. In addition, a water-soluble high-molecular compound (e.g. gum arabic) and/or a pH regulator (e.g. phosphoric acid) are incorporated. The water-soluble sugars are aldose, ketose, oligosaccharide, or sugar-alcohol. The aforesaid water-soluble sugars are cane sugar, grape sugar, fruit sugar, malt sugar, or milk sugar. By using this dampening water, filling up of ink in a water rod of a printing press and peeling of an ink supply roller can be inhibited at the time of lithographic printing and a water tolerance can be extended.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a high-performance fountain solution composition for lithographic printing, which has the feature of suppressing the entanglement of emulsified ink on a water stick of a printing machine during lithographic printing, and which is also designed to prevent contamination of the working environment. Regarding things.

[0002]

2. Description of the Related Art In offset printing, dampening water is supplied to the non-image area of a printing plate to prevent ink from adhering to the non-image area. The ink on the printing plate is usually in an emulsion state containing dampening water, but good printing quality can be obtained only when the emulsion is stable in an appropriate state (water content etc.). Generally, when the fountain solution on the printing plate is insufficient, the non-image area is soiled. Further, when the dampening water is excessive, the image area becomes thin. Volatile low C: O (ratio of carbon number to oxygen number) alcohols, which are generally represented by isopropyl alcohol (hereinafter referred to as IPA), as surface tension reducing agents and thickeners used in fountain solution for lithographic printing. (Specifically, C: O is 3 or less such as methanol and ethanol). However, in recent years, printing houses tend to stop using volatile components in dampening water as much as possible to improve the environment. This causes the surface tension of the dampening water to increase or the viscosity of the dampening water to decrease, resulting in entanglement of the water rod (the ink is entangled in the water rod due to a decrease in the flowability of the ink due to excessive emulsification) and roller peeling. (Because of the lack of water absorption “emulsification” of ink, water is left on the roller and the ink on the roller is peeled off.) It causes a problem when the emulsification property is deteriorated.
To solve this problem, when a non-volatile surfactant is used in the fountain solution, the water content of the emulsified ink on the printing machine tends to be high. In order to prevent this, when the amount of the surfactant added is suppressed, the water retention capacity of the ink decreases, and the emulsification tends to become unstable. That is, the fluctuation range of the supply amount of dampening water that can maintain high print quality (hereinafter collectively referred to as water width).
Narrows.

[0003]

DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted research on dampening water for solving the above-mentioned problems, that is, dampening water having a function of suppressing deterioration of roller peeling while improving entanglement with a water rod. As a result, the present invention has been completed.

[0004]

The present invention relates to a fountain solution composition for lithographic printing, which comprises a water-soluble saccharide.

According to the present invention, it is possible to provide a dampening solution having an outstanding high-speed printing suitability in which the water bar entanglement and the roller peeling are simultaneously improved and the water width is widened.

In the present invention, if the mechanism for simultaneously improving both the above-mentioned properties is not always clear, it is inferred at the present time that the water-soluble saccharide contains a large number of hydroxyl groups and constitutes this water-soluble saccharide. Since the hydrocarbon chain has hydroxyl groups (C: O is 1 or less) as many as the number of carbon atoms, it is presumed that the water-soluble saccharide improves water stick entanglement like the volatile alcohol. In addition, since water-soluble saccharides that have a solid structure at room temperature and atmospheric pressure have a lower vapor pressure than volatile alcohol and do not cause a significant decrease in environmental hygiene around the printing press, it is estimated that the occurrence of pollution can be suppressed as much as possible. .

Examples of the water-soluble sugars used in the present invention include aldoses such as glucose (glucose), xylose, galactose, arabinose and mannose; ketose such as fructose (fructose), sorbose and ribulose; sucrose (sucrose) and maltose ( Maltose), lactose (lactose), melibiose, raffinose, and other oligosaccharides; sorbitol, mannitol, reduced maltose, and other sugar alcohols (reducing sugars), and the like. These can be used alone or in admixture of two or more. be able to.

To add the water-soluble saccharide of the present invention to dampening water, 0.10% by weight to 1.0% by weight of the dampening water is directly added.
It may be added to the dampening water tank of the printing machine at an addition rate of% by weight, or more preferably, it may be added and mixed into the dampening water etchant as described below prior to the adjustment of the dampening water. If the addition rate is less than 0.10% by weight, the effect of the present invention is not exhibited,
On the other hand, when the weight exceeds 1.0%, the probability that the printed matter is wound up on the printing cylinder (blanket) is significantly increased and the gloss of the printed matter is adversely affected, which is not preferable.

Other than the water-soluble saccharides used in the fountain solution composition for lithographic printing according to the present invention, various raw materials constituting ordinary lithographic fountain solution can be mentioned, which are shown below. 1 or 2 selected arbitrarily from the compound group
Although it can be used in combination of two or more kinds, for example, gum arabic, polypropylene glycol monobutyl ether, polyvinylidone, polyvinyl alcohol,
Water-soluble polymer compounds such as polyacrylic acid, sodium polyacrylate, polyethylene glycol, sodium alginate, water-soluble cellulose ether, carboxymethyl cellulose, hydroxypropyl cellulose, aminoethyl cellulose, and derivatives thereof; ethylene glycol,
Water-soluble low molecular weight compounds such as glycerin and pentaerythritol; Phosphorus modifiers such as phosphoric acid, citric acid, oxalic acid, tannic acid, sulfuric acid and dichromic acid; any selected from carboxyl group, hydroxyl group, ester bond and ether bond Aliphatic, aromatic and alicyclic sulfonic acids having or not having a functional group or a chemical bond, and sodium salts and ammonium salts of these acids; emulsion type silicone oils and the like can be mentioned, usually an aqueous solution or an aqueous homogeneous solution. It can be used in the form of a dispersion. Furthermore, it is possible to use a thickener in combination depending on the type or setting of the dampening water supply portion of the printing machine.

As the ink used in the present invention, any of ordinary lithographic printing inks can be used.

[0011]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples. However, "%" in Examples and Comparative Examples means "% by weight with respect to the fountain solution".

Examples 1 to 5 and Comparative Examples 1 to 5 Fountain solutions 1 to 5 and Inks A to C were prepared by the following formulations.

Composition of fountain solution 1: gum arabic 0.02% (using IPA) diammonium citrate 0.01% sodium nitrate 0.01% IPA 10.00% gluconic acid 0.01% water 89.40 %

Composition of fountain solution 2: gum arabic 0.02% (using saccharides) diammonium citrate 0.01% sodium nitrate 0.01% polyethylene glycol (molecular weight 500,000) 0.01% sucrose 0.50% Water 99.45%

Composition of fountain solution 3: Gum arabic 0.02% (using saccharides) Secondary ammonium citrate 0.01% Sodium nitrate 0.01% Polyethylene glycol (molecular weight 500,000) 0.01% Glucose 0.50% Water 99.45%

Composition of fountain solution 4: Gum arabic 0.02% (using saccharides) Secondary ammonium citrate 0.01% Sodium nitrate 0.01% Polyethylene glycol (molecular weight 500,000) 0.01% Fructose 0.50% Water 99.45%

Composition of fountain solution 5: Polyethylene glycol (molecular weight 20,000) 0.01% (Propylene glycol monoethyl ether 0.02% without sugars and IPA ethylene glycol 0.01% Reference composition) Metaphosphoric acid 0.01 % Butyl acetate cellosolve 0.20% Citric acid 0.02% Secondary ammonium citrate 0.01% Water 99.72%

Composition of Ink A: Diallyl phthalate resin 17.50% Pigment (Carmine 6B-236) 18.10% Monomer (dipentaerythritol hexaalkylate) 55.50% Polymerization initiator (2-methyl-1- ( 4-Methylthio) -2-8.90% Morpholinopropanone-1)

Composition of Ink B: Rosin phenolic resin 61.00% varnish Pigment (Carmine 6B-236) 18.00% Solvent (No. 7 solvent) 21.00%

Composition of Ink C: Flaxseed oil modified rosin phenol resin 70.00% varnish Pigment (Carmine 6B-236) 18.00% Dryer (Co-Mn mixed metal salt) 1.00% Solvent (No. 6 solvent) 11.00%

Using dampening waters 1 to 5 and inks A to C,
Tables 1 and 2 show the results of the water rod entanglement, roller peeling, and water width tests conducted on a Roland R-201 printing machine. The numbers in the table are 5 grades, 5 being excellent and 1 being poor. From this table, the fountain solution containing water-soluble sugars is more useful than the case of using a fountain solution containing no water-soluble saccharide in that it suppresses water bar entanglement and roller peeling at the same time. It can be seen that the water width at the time of printing of the sheet and the off wheel is improved. In particular, the comparison between Example 1 and Comparative Example 5 and the comparison between Examples 3, 4, 5 and Comparative Example 4
It can be seen that the fountain solution of the present invention is superior in roller peeling resistance and water rod entanglement resistance as compared with the conventional fountain solution containing no isopropyl alcohol.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

By using the dampening water according to the present invention, it is possible to suppress the entanglement of the ink on the water rod of the printing machine and the peeling of the ink supply roller during lithographic printing, and it is possible to increase the water width.

Claims (4)

[Claims] 1. A fountain solution composition for lithographic printing, which comprises a water-soluble saccharide. 2. The fountain solution composition for lithographic printing according to claim 1, which contains a water-soluble polymer compound and / or a pH adjuster. 3. The fountain solution composition for lithographic printing according to claim 1, wherein the water-soluble saccharide is an aldose, a ketose, an oligosaccharide or a sugar alcohol. 4. The fountain solution composition for lithographic printing according to claim 1 or 2, wherein the water-soluble saccharide is sucrose, glucose, fructose, maltose or lactose.